glib/gthread.h

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GLib Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 #ifndef __G_THREAD_H__
  28 #define __G_THREAD_H__
  29
  30 #include <glib/gerror.h>
  31 #include <glib/gtypes.h>
  32 #include <glib/gatomic.h>  /* for g_atomic_pointer_get */
  33
  34 G_BEGIN_DECLS
  35
  36 /* GLib Thread support
  37  */
  38
  39 extern GQuark g_thread_error_quark (void);
  40 #define G_THREAD_ERROR g_thread_error_quark ()
  41
  42 typedef enum
  43 {
  44   G_THREAD_ERROR_AGAIN /* Resource temporarily unavailable */
  45 } GThreadError;
  46
  47 typedef gpointer (*GThreadFunc) (gpointer data);
  48
  49 typedef enum
  50 {
  51   G_THREAD_PRIORITY_LOW,
  52   G_THREAD_PRIORITY_NORMAL,
  53   G_THREAD_PRIORITY_HIGH,
  54   G_THREAD_PRIORITY_URGENT
  55 } GThreadPriority;
  56
  57 typedef struct _GThread         GThread;
  58 struct  _GThread
  59 {
  60   /*< private >*/
  61   GThreadFunc func;
  62   gpointer data;
  63   gboolean joinable;
  64   GThreadPriority priority;
  65 };
  66
  67 typedef struct _GMutex          GMutex;
  68 typedef struct _GCond           GCond;
  69 typedef struct _GPrivate        GPrivate;
  70 typedef struct _GStaticPrivate  GStaticPrivate;
  71
  72 typedef struct _GThreadFunctions GThreadFunctions;
  73 struct _GThreadFunctions
  74 {
  75   GMutex*  (*mutex_new)           (void);
  76   void     (*mutex_lock)          (GMutex               *mutex);
  77   gboolean (*mutex_trylock)       (GMutex               *mutex);
  78   void     (*mutex_unlock)        (GMutex               *mutex);
  79   void     (*mutex_free)          (GMutex               *mutex);
  80   GCond*   (*cond_new)            (void);
  81   void     (*cond_signal)         (GCond                *cond);
  82   void     (*cond_broadcast)      (GCond                *cond);
  83   void     (*cond_wait)           (GCond                *cond,
  84                                    GMutex               *mutex);
  85   gboolean (*cond_timed_wait)     (GCond                *cond,
  86                                    GMutex               *mutex,
  87                                    GTimeVal             *end_time);
  88   void      (*cond_free)          (GCond                *cond);
  89   GPrivate* (*private_new)        (GDestroyNotify        destructor);
  90   gpointer  (*private_get)        (GPrivate             *private_key);
  91   void      (*private_set)        (GPrivate             *private_key,
  92                                    gpointer              data);
  93   void      (*thread_create)      (GThreadFunc           func,
  94                                    gpointer              data,
  95                                    gulong                stack_size,
  96                                    gboolean              joinable,
  97                                    gboolean              bound,
  98                                    GThreadPriority       priority,
  99                                    gpointer              thread,
 100                                    GError              **error);
 101   void      (*thread_yield)       (void);
 102   void      (*thread_join)        (gpointer              thread);
 103   void      (*thread_exit)        (void);
 104   void      (*thread_set_priority)(gpointer              thread,
 105                                    GThreadPriority       priority);
 106   void      (*thread_self)        (gpointer              thread);
 107   gboolean  (*thread_equal)       (gpointer              thread1,
 108                                    gpointer              thread2);
 109   guint64   (*gettime)            (void);
 110 };
 111
 112 GLIB_VAR GThreadFunctions       g_thread_functions_for_glib_use;
 113 GLIB_VAR gboolean               g_thread_use_default_impl;
 114 GLIB_VAR gboolean               g_threads_got_initialized;
 115
 116 /* initializes the mutex/cond/private implementation for glib, might
 117  * only be called once, and must not be called directly or indirectly
 118  * from another glib-function, e.g. as a callback.
 119  */
 120 void    g_thread_init   (GThreadFunctions       *vtable);
 121
 122 /* Errorcheck mutexes. If you define G_ERRORCHECK_MUTEXES, then all
 123  * mutexes will check for re-locking and re-unlocking */
 124
 125 /* Initialize thread system with errorcheck mutexes. vtable must be
 126  * NULL. Do not call directly. Use #define G_ERRORCHECK_MUTEXES
 127  * instead.
 128  */
 129 void    g_thread_init_with_errorcheck_mutexes (GThreadFunctions* vtable);
 130
 131 /* A random number to recognize debug calls to g_mutex_... */
 132 #define G_MUTEX_DEBUG_MAGIC 0xf8e18ad7
 133
 134 #ifdef G_ERRORCHECK_MUTEXES
 135 #define g_thread_init(vtable) g_thread_init_with_errorcheck_mutexes (vtable)
 136 #endif
 137
 138 /* internal function for fallback static mutex implementation */
 139 GMutex* g_static_mutex_get_mutex_impl   (GMutex **mutex);
 140
 141 #define g_static_mutex_get_mutex_impl_shortcut(mutex) \
 142   (g_atomic_pointer_get ((gpointer*)(void*)mutex) ? *(mutex) : \
 143    g_static_mutex_get_mutex_impl (mutex))
 144
 145 /* shorthands for conditional and unconditional function calls */
 146
 147 #define G_THREAD_UF(op, arglist)                                        \
 148     (*g_thread_functions_for_glib_use . op) arglist
 149 #define G_THREAD_CF(op, fail, arg)                                      \
 150     (g_thread_supported () ? G_THREAD_UF (op, arg) : (fail))
 151 #define G_THREAD_ECF(op, fail, mutex, type)                             \
 152     (g_thread_supported () ?                                            \
 153       ((type(*)(GMutex*, const gulong, gchar const*))                   \
 154       (*g_thread_functions_for_glib_use . op))                          \
 155      (mutex, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : (fail))
 156
 157 #ifndef G_ERRORCHECK_MUTEXES
 158 # define g_mutex_lock(mutex)                                            \
 159     G_THREAD_CF (mutex_lock,     (void)0, (mutex))
 160 # define g_mutex_trylock(mutex)                                         \
 161     G_THREAD_CF (mutex_trylock,  TRUE,    (mutex))
 162 # define g_mutex_unlock(mutex)                                          \
 163     G_THREAD_CF (mutex_unlock,   (void)0, (mutex))
 164 # define g_mutex_free(mutex)                                            \
 165     G_THREAD_CF (mutex_free,     (void)0, (mutex))
 166 # define g_cond_wait(cond, mutex)                                       \
 167     G_THREAD_CF (cond_wait,      (void)0, (cond, mutex))
 168 # define g_cond_timed_wait(cond, mutex, abs_time)                       \
 169     G_THREAD_CF (cond_timed_wait, TRUE,   (cond, mutex, abs_time))
 170 #else /* G_ERRORCHECK_MUTEXES */
 171 # define g_mutex_lock(mutex)                                            \
 172     G_THREAD_ECF (mutex_lock,    (void)0, (mutex), void)
 173 # define g_mutex_trylock(mutex)                                         \
 174     G_THREAD_ECF (mutex_trylock, TRUE,    (mutex), gboolean)
 175 # define g_mutex_unlock(mutex)                                          \
 176     G_THREAD_ECF (mutex_unlock,  (void)0, (mutex), void)
 177 # define g_mutex_free(mutex)                                            \
 178     G_THREAD_ECF (mutex_free,    (void)0, (mutex), void)
 179 # define g_cond_wait(cond, mutex)                                       \
 180     (g_thread_supported () ? ((void(*)(GCond*, GMutex*, gulong, gchar*))\
 181       g_thread_functions_for_glib_use.cond_wait)                        \
 182         (cond, mutex, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : (void) 0)
 183 # define g_cond_timed_wait(cond, mutex, abs_time)                       \
 184     (g_thread_supported () ?                                            \
 185       ((gboolean(*)(GCond*, GMutex*, GTimeVal*, gulong, gchar*))        \
 186         g_thread_functions_for_glib_use.cond_timed_wait)                \
 187           (cond, mutex, abs_time, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : TRUE)
 188 #endif /* G_ERRORCHECK_MUTEXES */
 189
 190 #define g_thread_supported()    (g_threads_got_initialized)
 191 #define g_mutex_new()            G_THREAD_UF (mutex_new,      ())
 192 #define g_cond_new()             G_THREAD_UF (cond_new,       ())
 193 #define g_cond_signal(cond)      G_THREAD_CF (cond_signal,    (void)0, (cond))
 194 #define g_cond_broadcast(cond)   G_THREAD_CF (cond_broadcast, (void)0, (cond))
 195 #define g_cond_free(cond)        G_THREAD_CF (cond_free,      (void)0, (cond))
 196 #define g_private_new(destructor) G_THREAD_UF (private_new, (destructor))
 197 #define g_private_get(private_key) G_THREAD_CF (private_get, \
 198                                                 ((gpointer)private_key), \
 199                                                 (private_key))
 200 #define g_private_set(private_key, value) G_THREAD_CF (private_set, \
 201                                                        (void) (private_key = \
 202                                                         (GPrivate*) (value)), \
 203                                                        (private_key, value))
 204 #define g_thread_yield()              G_THREAD_CF (thread_yield, (void)0, ())
 205
 206 #define g_thread_create(func, data, joinable, error)                    \
 207   (g_thread_create_full (func, data, 0, joinable, FALSE,                \
 208                          G_THREAD_PRIORITY_NORMAL, error))
 209
 210 GThread* g_thread_create_full  (GThreadFunc            func,
 211                                 gpointer               data,
 212                                 gulong                 stack_size,
 213                                 gboolean               joinable,
 214                                 gboolean               bound,
 215                                 GThreadPriority        priority,
 216                                 GError               **error);
 217 GThread* g_thread_self         (void);
 218 void     g_thread_exit         (gpointer               retval);
 219 gpointer g_thread_join         (GThread               *thread);
 220
 221 void     g_thread_set_priority (GThread               *thread,
 222                                 GThreadPriority        priority);
 223
 224 /* GStaticMutexes can be statically initialized with the value
 225  * G_STATIC_MUTEX_INIT, and then they can directly be used, that is
 226  * much easier, than having to explicitly allocate the mutex before
 227  * use
 228  */
 229 #define g_static_mutex_lock(mutex) \
 230     g_mutex_lock (g_static_mutex_get_mutex (mutex))
 231 #define g_static_mutex_trylock(mutex) \
 232     g_mutex_trylock (g_static_mutex_get_mutex (mutex))
 233 #define g_static_mutex_unlock(mutex) \
 234     g_mutex_unlock (g_static_mutex_get_mutex (mutex))
 235 void g_static_mutex_init (GStaticMutex *mutex);
 236 void g_static_mutex_free (GStaticMutex *mutex);
 237
 238 struct _GStaticPrivate
 239 {
 240   /*< private >*/
 241   guint index;
 242 };
 243 #define G_STATIC_PRIVATE_INIT { 0 }
 244 void     g_static_private_init           (GStaticPrivate   *private_key);
 245 gpointer g_static_private_get            (GStaticPrivate   *private_key);
 246 void     g_static_private_set            (GStaticPrivate   *private_key,
 247                                           gpointer          data,
 248                                           GDestroyNotify    notify);
 249 void     g_static_private_free           (GStaticPrivate   *private_key);
 250
 251 typedef struct _GStaticRecMutex GStaticRecMutex;
 252 struct _GStaticRecMutex
 253 {
 254   /*< private >*/
 255   GStaticMutex mutex;
 256   guint depth;
 257   GSystemThread owner;
 258 };
 259
 260 #define G_STATIC_REC_MUTEX_INIT { G_STATIC_MUTEX_INIT }
 261 void     g_static_rec_mutex_init        (GStaticRecMutex *mutex);
 262 void     g_static_rec_mutex_lock        (GStaticRecMutex *mutex);
 263 gboolean g_static_rec_mutex_trylock     (GStaticRecMutex *mutex);
 264 void     g_static_rec_mutex_unlock      (GStaticRecMutex *mutex);
 265 void     g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 266                                          guint            depth);
 267 guint    g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex);
 268 void     g_static_rec_mutex_free        (GStaticRecMutex *mutex);
 269
 270 typedef struct _GStaticRWLock GStaticRWLock;
 271 struct _GStaticRWLock
 272 {
 273   /*< private >*/
 274   GStaticMutex mutex;
 275   GCond *read_cond;
 276   GCond *write_cond;
 277   guint read_counter;
 278   gboolean have_writer;
 279   guint want_to_read;
 280   guint want_to_write;
 281 };
 282
 283 #define G_STATIC_RW_LOCK_INIT { G_STATIC_MUTEX_INIT, NULL, NULL, 0, FALSE, 0, 0 }
 284
 285 void      g_static_rw_lock_init           (GStaticRWLock* lock);
 286 void      g_static_rw_lock_reader_lock    (GStaticRWLock* lock);
 287 gboolean  g_static_rw_lock_reader_trylock (GStaticRWLock* lock);
 288 void      g_static_rw_lock_reader_unlock  (GStaticRWLock* lock);
 289 void      g_static_rw_lock_writer_lock    (GStaticRWLock* lock);
 290 gboolean  g_static_rw_lock_writer_trylock (GStaticRWLock* lock);
 291 void      g_static_rw_lock_writer_unlock  (GStaticRWLock* lock);
 292 void      g_static_rw_lock_free           (GStaticRWLock* lock);
 293
 294 void      g_thread_foreach                (GFunc          thread_func,
 295                                            gpointer       user_data);
 296
 297 typedef enum
 298 {
 299   G_ONCE_STATUS_NOTCALLED,
 300   G_ONCE_STATUS_PROGRESS,
 301   G_ONCE_STATUS_READY
 302 } GOnceStatus;
 303
 304 typedef struct _GOnce GOnce;
 305 struct _GOnce
 306 {
 307   volatile GOnceStatus status;
 308   volatile gpointer retval;
 309 };
 310
 311 #define G_ONCE_INIT { G_ONCE_STATUS_NOTCALLED, NULL }
 312
 313 gpointer g_once_impl (GOnce *once, GThreadFunc func, gpointer arg);
 314
 315 #ifdef G_ATOMIC_OP_MEMORY_BARRIER_NEEDED
 316 # define g_once(once, func, arg) g_once_impl ((once), (func), (arg))
 317 #else /* !G_ATOMIC_OP_MEMORY_BARRIER_NEEDED*/
 318 # define g_once(once, func, arg) \
 319   (((once)->status == G_ONCE_STATUS_READY) ? \
 320    (once)->retval : \
 321    g_once_impl ((once), (func), (arg)))
 322 #endif /* G_ATOMIC_OP_MEMORY_BARRIER_NEEDED */
 323
 324 /* these are some convenience macros that expand to nothing if GLib
 325  * was configured with --disable-threads. for using StaticMutexes,
 326  * you define them with G_LOCK_DEFINE_STATIC (name) or G_LOCK_DEFINE (name)
 327  * if you need to export the mutex. With G_LOCK_EXTERN (name) you can
 328  * declare such an globally defined lock. name is a unique identifier
 329  * for the protected varibale or code portion. locking, testing and
 330  * unlocking of such mutexes can be done with G_LOCK(), G_UNLOCK() and
 331  * G_TRYLOCK() respectively.
 332  */
 333 extern void glib_dummy_decl (void);
 334 #define G_LOCK_NAME(name)               g__ ## name ## _lock
 335 #ifdef  G_THREADS_ENABLED
 336 #  define G_LOCK_DEFINE_STATIC(name)    static G_LOCK_DEFINE (name)
 337 #  define G_LOCK_DEFINE(name)           \
 338     GStaticMutex G_LOCK_NAME (name) = G_STATIC_MUTEX_INIT
 339 #  define G_LOCK_EXTERN(name)           extern GStaticMutex G_LOCK_NAME (name)
 340
 341 #  ifdef G_DEBUG_LOCKS
 342 #    define G_LOCK(name)                G_STMT_START{             \
 343         g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
 344                "file %s: line %d (%s): locking: %s ",             \
 345                __FILE__,        __LINE__, G_GNUC_PRETTY_FUNCTION, \
 346                #name);                                            \
 347         g_static_mutex_lock (&G_LOCK_NAME (name));                \
 348      }G_STMT_END
 349 #    define G_UNLOCK(name)              G_STMT_START{             \
 350         g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
 351                "file %s: line %d (%s): unlocking: %s ",           \
 352                __FILE__,        __LINE__, G_GNUC_PRETTY_FUNCTION, \
 353                #name);                                            \
 354        g_static_mutex_unlock (&G_LOCK_NAME (name));               \
 355      }G_STMT_END
 356 #    define G_TRYLOCK(name)                                       \
 357         (g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                  \
 358                "file %s: line %d (%s): try locking: %s ",         \
 359                __FILE__,        __LINE__, G_GNUC_PRETTY_FUNCTION, \
 360                #name), g_static_mutex_trylock (&G_LOCK_NAME (name)))
 361 #  else  /* !G_DEBUG_LOCKS */
 362 #    define G_LOCK(name) g_static_mutex_lock       (&G_LOCK_NAME (name))
 363 #    define G_UNLOCK(name) g_static_mutex_unlock   (&G_LOCK_NAME (name))
 364 #    define G_TRYLOCK(name) g_static_mutex_trylock (&G_LOCK_NAME (name))
 365 #  endif /* !G_DEBUG_LOCKS */
 366 #else   /* !G_THREADS_ENABLED */
 367 #  define G_LOCK_DEFINE_STATIC(name)    extern void glib_dummy_decl (void)
 368 #  define G_LOCK_DEFINE(name)           extern void glib_dummy_decl (void)
 369 #  define G_LOCK_EXTERN(name)           extern void glib_dummy_decl (void)
 370 #  define G_LOCK(name)
 371 #  define G_UNLOCK(name)
 372 #  define G_TRYLOCK(name)               (TRUE)
 373 #endif  /* !G_THREADS_ENABLED */
 374
 375
 376 G_END_DECLS
 377
 378 #endif /* __G_THREAD_H__ */